Drill pipe connection



May 22, 1951 A. L. STONE DRILL PIPE CONNECTION 9 Sheets-Sheet 1 FiledSept. 1'7, 1945 m i "E 6 H i I L am a h 2 m i M an a j 3 I I/vZr May 22,1951 A. L. STONE 2,553,335

DRILL PIPE CONNECTION 7 Filed Sept. 17, 1945 9 Sheets-Sheet 2 [Hr/Eu?1'02" :H/berf L 52 -0175 May 22, 1951 A. L. STONE 5 mum. PIPE commonFiled Sept. 17, 1945 9 Sheets-Sheet 3 [27 V927 for =Z1b5rf L 5 fans May22, 1951 A. L. STONE mm. PIPE CONNECTION t m OHM, N glwfi 0.2 a Y WM WEv May 22,, 1951 A. L. s'roN 2,553,836-

DRILL PIPE CONNECTION Filed Sept. 17, 1945 9 Sheets-Sheet 6 #ZJE.

May 22, 1951 A. L. STONE v 3,

DRILL PIPE CONNECTION Filed Sept. 17, 1945 9 Sheets-Sheet 9 Patented May22, 1951 DRILL PIPE CONNECTION- Albert L. Stone, Palos Verdes Estates,Calif., as-

signor to Hydril Corporation, Los Angeles, Calif., a corporation ofCalifornia Application September 17, E345, Serial N0. 616,739

6 Claims.

This invention relates generally to drill pipe connections and methodsof making them, and is more particularly concerned with connections andmethods involving the use of hard solder.

For the purpose of explaining my invention, I will describe it inconnection with a joint employing a particular type of thread, but itwill be understood that this choice is made for illustrative purposesonly and is not to be considered as limitative on the invention.

A drill stem for boring oil wells and the like, ordinarily includes aseries of stands, each stand being made up, for instance, of severallengths of drill pipe which are more or less permanently connected bycollar couplings. Between each stand is interposed a tool joint made upof a pair of members (one a box member and the other a pin member)having interengageable, quick-detachable threads, whereby it requiresonly a few turns to couple or uncouple them.

The box and pin members of a given pair are connected to the pipes atthe opposing ends of adjacent stands, and the present invention may beapplied with particular advantage to the connections between the pipesand joint members. I have therefore confined my illustrations anddescription to such an application. However, such confinement is not tobe considered as indicating that the usefulness of the invention nor theappended claims are limited to the illustrated and describedinstallations.

Each of the connections between the pipes and their associated tooljoint members, is ordinarily in the form of interfitting, taperedthreads (the taper being appreciably less than that of thequick-detachable connections mentioned above). It is important thatthese connections be made up tightly in order to seal against leakagedue to the high differentials frequently existing between external andinternal fluid pressures. The radial forces developed by tightlyengaging the sealing surfaces and then exposing the joint to high torqueloads during drilling operations, tend to split the box members and tocollapse the pin members, and are thus the cause of frequent failures,it being remembered that the pin member is tapered and that the socketof the box member is complementary to the pin. The creeping of thethreads under high torque loads and the relative working of thejointparts under service conditions, particularly where initiallooseness exists in the joint, are recognized as starting factors ofultimate failure.

In usual connections, the last engaged thread establishes the zone atwhich failure is most likely to occur. This is because it is about thisthread, which represents a sharply defined annular groove in the pinmember, that the joint members tend to rock relatively as the drill pipebends during drilling operations. The valley of this last engaged threadrepresents a relatively weak zone, as it amounts to a notch whichinvites the initiation of rupture at this point. The relative rocking ofthe joint parts set up stresses and strains of fatigue at thisrelatively weakened zone, which areprobably the most frequent causes oftwist-01f failures.

The box of an A. P. 1. joint includes an unthreaded skirt that extendslongitudinally outward beyond the last engaged thread, but this does notcure the situation spoken of above since the annular spacing of theskirt from the pipe is of a magnitude to allow a dangerous amount ofrocking.

It is therefore among the objects of the invention to provide afluid-tight connection wherein the joint members are relativelyimmobilized so that there can be no accidental loosening of the threadedconnection, no creeping of threads which might lead to box-splitting orpin collapse, and no initial looseness which might otherwise giveopportunity for the joint to work. Further, it is an object of theinvention to provide a connection wherein the point of rock does notexist at the last engaged thread, but, rather, is shifted longitudinallyoutward to an unthreaded part of the pin member where norupture-inviting notches exist. It is a still further object of theinvention to provide a connection wherein the joint members, whilerigidly immobilized when the joint is in use, may bev readilydisconnected when occasion arises for the wilful breaking of the joint.However, after the joint has been so parted, it is in condition to bereconnected with its parts again relatively immobilized.

In my copending application Ser. No. 531,380, entitled Soldered DrillPipe Connections and Method of Making Same, filed April 17, 1944, nowabandoned, I have shown and described a connection and method whereinall the above objects are accomplished by the use of hard solder. Inthat application it is pointed out that the thickness of the solder bondis a critical factor; in fact, to give fully efiective results the bondmust be of uniform capillary thickness. In one of the showings of thatapplication, the width of the solder receiving space between jointmembers was established by the direct machining of opposed peripheralfaces of the box and pin members at a point longitudinally outward ofthe mating threads, and, since the space was of capillary magnitude,this machining necessarily had to be of a relatively high degree ofaccuracy.

It is a particular object of the present invention to secure thebenefits recited above without requiring the close-tolerance machiningof the faces to be bonded, and thus not only make it possible to reducethe labor and cost of manufacture, but also to reduce the manufacturingproblem to an extent that it may be practiced readily and profitably inthe field, even though manufacturing facilities be relatively meager.

Generally, the present invention is adapted" to situations where thereis an annular spacehof considerable width, (that is, considerablygreater than of capillary extent) between the pin and box at a pointoutwardly beyond the last engaged thread of the joint, whether thisspace be the result of original design or represents one of the initialsteps of the present method. In carrying out the present method. it isonly necessary'that portions of the unthreaded peripheral faces of thepin and box members be substantially concentric with the pin and boxthreads, respectively, and that the annular space defined between saidfaces be of appreciably greater than capillary extent. Thus, theradially measured width of the space will be substantially uniformthroughout its circumferential extent, but its dimensional value is notcritical. To establish the critical, capillary Spacing, I utilize a gagering which, when inserted in the annular space, serves as a gage toestablish, with opposing, peripheral faces of the joint members,annular, solder-reception spaces of capillary width. Where conditionscall for a bond of highest ultimate strength, the gage rings are sofashioned that it is assured that the space is of exactly uniform widththroughout the circumference of the bond and throughout an appreciablelongitudinal extent.

Thus the gage ring serves the purpose of establishing an annularsolder-receiving space of predetermined critical width, regardless ofthe original spacing of the opposed peripheral faces of the box and pinmembers.

Upon bonding the ring and joint members by hard solder introduced to thecapillary spaces created as above, the ring becomes, in efiect, anintegral part of the coupled joint, acting with the introduced. solder,as a filler for. the space originally existing between the jointmembers, and as an intermediate. integrating tie between said members.

The ring and introduced solder, in their filling function, serve toeliminate free, relative transverse movement of portions of the jointmembers, such as is possible at points where the members are annularlyspaced apart. By filling the gap between joint members at a pointoutward-1y. beyond the last engaged thread, there is no tendency for themembers to rockrelatively about the zone of this last thread when thedrill pipe is exposed to bending stresses and strains and. therefore,there is no likelihood of failure at this zone. Additionally, thesoldered ringties or integrates the joint members so that theyeffectively resist the tendencies arising from stresses of tension,compression and torque to loosen the threaded joint, to cause threadcreep, and to create initial looseness which might otherwise developinto a tendency of the joint members to wor It is a distinguishingcharacteristic of the finished joint that the ring acts not only as afiller 4 or shim, but also as an integral, rigid bridge between jointmembers, which is as fully effective to transmit drive from member tomember and to prevent relative movement between the members as thoughthose members were one.

Other objects and features of novelty will be apparent from thefollowing detailed description, reference being made to the accompanyingdrawings, in which:

Fig. 1 is an elevation, partly in medial section, showing an embodimentof my invention applied to'the tool'joint of a drill pipe;

Fig. 2 is an enlarged, fragmentary view of one of the connections shownin Fig. 1 prior to its completion; 1

Fig.3 is an enlarged fragmentary section corresponding to the zone A inFig. 2, but illustrating a standard A. P. I. connection to which thegage ring of my invention has not yet been applied;

Fig. 4 is an enlarged fragmentary section corresponding to the zone A inFig. 2, but additionally illustrating the initial application of a gagering to the pin member of the joint;

Fig. 5 is a view similar to Fig. 4, but showing a later step of themethod;

Fig. 6 is a view of the completed connection and represents afragmentary enlargement of one of the connections shown in Fig. 1;

Fig. '7 is a reduced-scale section on line 1--1 of Fig. 6, but showingthe connection in its com plete, annular form;

Fig. 8 is a View similar to Fig. 4, but showing a different type of gagering;

Fig. 9 is a reduced-scale section on line 9!! of Fig.8, but showing thejoint member and'gage ring in their complete, annular forms;

Figs. 10 and 11 are similar to Fig. 9, but showing variational gagerings;

Fig. 12 is a fragmentary perspective of the gage ring illustrated inFig. 9;

Fig. 13 is a view similar to Fig. 8, but showing a later step incarrying out the method Fig. 14 is a view similar to Fig. 13,- butshow-' ing the connection completed;

Figs. 15, 16 and 17 are similar to Figs. 8, i3, and- 14, respectively,but showing different gage ring' and counterbore formations;

Figs. 18, 19 and 20 are similar to Figs. 8, 13 and- 14, respectively,but showin different gage ring and pin formations;

Fig. 21 is a View similar to Fig. 16, but showing a different gage ringand showing a different placement of the solder ring;

Fig. 22 is a fragmentary perspective of the gag ring shown in Fig. 21;

Fig. 23 is a View similar to Fig. 21, but showing the connectioncompleted;

Fig. 24 is a View similar to Fig. 4, but showing the pin member ofreduced diameter adjacent the threads, a relatively large initialclearance space between the gage ring and pin, and a'conventionalillustration of a ring-swaging means;

Fig. 25 is a reduced scale section on line 25-25 of Fig. 24 but showingthe elements in their full annular form;

Fig. 26 is a view similar to Fig. 24 but showing the gage ring insertedwithin the box counter bore;

Fig. 27 is a view similar to Fig. 26, but showingthe connectioncompleted;

Fig. 28 is a view similar to Fig. 4, but showing variational pin, gagering and counterbore for mations;

Fig. 29 is a view similar to Fig. 28, but showing a subsequent step inthe method;

Fig. 30 is a view similar to Fig. 29 but showing the connectioncompleted;

Fig. 31 is a view similar to Fig. 3, but showing the pin memberre-shaped, and a gage ring in its initial position on the pin member;

Fig. 32 is a view similar to Fig. 31, but showing a subsequent step inthe method; and

Fig. 33 is a view similar to Fig. 32 but showing the connectioncompleted;

Before entering into a detailed discussion of the invention, I will makecertain generalizations and reservations.

References to hard solder are to be considered as including the use ofany solder or brazing material which requires a red heat to meltit, andreferences to soldering operations are to be considered as applyingeither to soldering or to brazing. It will be understood that wheneverthe bonding material is such that flux is necessary or desirable, theoperation will include the use of a suitable flux, even though it be notspecifically mentioned hereinafter, and that the flux is applied fromthe point of solder introduction to all points to which it is indicatedthe molten solder is to run.

Capillary width of a space is to be considered as representing adimension which will permit or cause the feeding of solder therethroughby capillary action. For instance, the range between .0005" and .007 hasbeen found satisfactory. On the average, a width of about .003" ispreferred for the operation here to be described. A shoulder or flangeheight of capillary extent is to be considered as being of the sameorder of dimensions. These widths and heights are necessarily shown ongreatly exag- I gerated scale in the drawings, for obvious reasons.

It will be understood that while the invention is especially welladapted to the connection of tool joint members to adjoining pipesections, and is so illustrated and described, the invention and claimsare to be considered as broadly contemplating the application of themethod to any threaded connection between tubular members such as thosemaking up a well pipe.

Fig. 1 illustrates a fragment of a drill stem or pipe string I0 made upof adjacent drill pipe sections II and I2 detachably coupled by the tooljoint generally indicated at I3. Tool joint I3 comprises pin I4 and boxmember I5 which are, respectively, threadably connected to theinternally upset ends I 5 and ll of pipes II and I2, re-

ternally, is not at all controlling on the present invention.

Pin I8 of member I4 and box I9 of member I5 have a threaded connectionat 20 which is of the quick-detachable type, the pin and box beingrelatively sharply tapered so it requires only a few turns of one memberwith relation to the other to couple or uncouple them. Tool joints areemployed between adjacent stands of drill pipe, each stand normallybeing made up of a plurality of pipe sections.

Pipe sections II and I2 represent opposing sections of such adjacentstands, and tool joint I3 represents a point at which the drill stem isseparated into stands, when coming out of the hole, and at whichadjacent stands are connected into the stem when going into the hole.

The J nts 2! and 22 between pipe sections II,

connections are ordinarily intended to be perma-- nent ones, at leastuntil necessity arises for re-- placing the tool joints. Such permanenceis se-- cured, in the present instance, by a hard-solderedv bond. Whenoccasion arises for breaking the" connection, it requires only that thebond be heated to solder-flow temperature to insure that the subsequentunthreading operation may be accomplished without causing damage to thejoint members or pipe sections, including the coupling threads.

Joints or connections 2! and 22 are similar and therefore I willdescribe only one of them in detail. While I will refer to particularcharacteristics of the threads, this is done for illustrative purposes,only, and is not to be considered as limitative, for the invention isused to advantage irrespective of the nature of the threads. Connection2I will hereinafter be referred to as being between the pin memberrepresented by pipe terminal I6 (whether or not it be upset) and the boxmember represented by the collar ortion 23 of the tool-joint member I4.Members I6 and 23 have mating, tapered thread 24 and 25, the taperbeing, for instance, about 2, on the axis, as compared with the taper ofabout '7", on the axis, of thread 20, though, again, such degrees oftaper are not to be considered as limitative on the invention.

For purposes of explaining certain characteristics of a usual connectionbetween pipe and tool joint members and to lay the basis for laterreference to a particular embodiment of the invention, reference willfirst be made to Fig. 3, wherein there is illustrated a standard A. -P.I. connection and to which the description, so far given, applies fully.

' The thread cutting operation results in the gradual dying out of thepin threads, as at 26. Box member 23 is cylindrically counterbored at 27to provide a skirt 28 which i annularly spaced from, but extendslongitudinally over, the dieout of the thread. Thus, space 29 isannularly defined by the opposed peripheral faces 30 and 3| of the pinand box members, respectively. Tapered counterbore 32 extends inwardlyfrom counterbore 27 to the bore of the box in a manner to cause the lasttwo or three threads of the box member also to die-out, it resultingthat pin thread 33 normally represents the last fully-engaged thread ofthe pin member. Since there is no positive stop for limiting the extentto which the box and pin members are screwed together, the imposition ofheavy torque loads on the drill stem during drilling operations tends tocause thread-creep, which, due to the tapered nature of the box and pinmembers, often result in radial collapse of the pin member or splittingof the box member. Furthermore, due to the annular clearance existingbetween the pin and box members at a point outwardly beyond thread 33,said thread represents the rock point or location about which the jointmembers tend to rock relatively as the drill pipe bends during drillingoperations. The consequent concentration of stresses and strain offatigue at this zone, where the last engaged thread introduces thefactor of notch sensitivity, is a frequent cause of pipe-rupture.

In my co-pending application, identified above, it is pointed out thatby immobilizing the joint parts through a hard solder bond'at the freeend 'offthe box member, the above objectionable results'are avoided.However, as stressed in that application, the solder-bond must not be ofgreater than capillary thickness if the necessary joint-strength is tobe obtained. Obviously, therefore, a hard-solder bond having a thicknessequal to the radially measured width of space 29 will not do-for suchspace is normally about 1%" wide where the pipe H is of 4 /2" outsidediameter. In all standard A. P. I. joints the spaces corresponding to 29are of greater than capillary width.

Later, in connection with Figs. 31 through 33, I willdescribe how Iadapt my method to the soldering of a joint initially having thecharacteristics of Fig. 3, but I will now proceed to the description ofmy method as applied in a situation where the box member of theconnection is fashioned so it does not follow the A. P. I. standardinsofar as the annular skirt and the counterbore areconcerned.

Reference will first be made to Figs. 1, 2 and 4 through 7. Throughoutthe remainder of the specification, exactly corresponding parts of theseveral illustrated variational embodiments of the invention will begiven the same reference numerals, while parts which correspondgenerally but have individually different detail characteristics will begiven the same reference numerals followed by individual letter-indicia.This'is done to avoid the necessity of repetitive description.

In Figs. 2 and 4 the pin member l6 andv its threads 24 may be the sameas the corresponding parts of Fig. 3, it being assumed that threads 2are concentric with peripheral face 30 and that the latter is insolder-receptive condition or may be made so by merely cleaning it ofi.Box member 23a is generally similar to box 23, and its thread 25 maycorrespond exactly tothe box thread of Fig. 3, but counterbore Zia isof, greater diameter than is counterbore 21, so space 29a is, forexample, about twice as wide, measured radially, as is space 29, thoughthis particular relative dimension is not to be considered aslimitative. Preferably, also, skirt 28a is longer than skirt 28, thusadding in effect, to the depth of the counterbore 2 1a and to thelongitudinal extent of the zone in which peripheral face 31a radiallyopposes an unthreaded extent of the peripheral face of the pin member.

It is not necessary that counterbore 21a be machined to any exactdiameter, but it is quite important that peripheral face 3la beconcentric with box threads 25. With this condition of concentricityexisting, and since it has been specified that face 30 is concentricwith pin thread 24, it is assured that, when threads 24 and 25 areproperly mated, faces 30 and 3 la are concentric and space 29a is ofuniform width throughout its annular extent.

Though the opposed faces of the pin and box members may be machined tohave precise relative dimensions, as may also the gage ring (to bedescribed) to allow for universal interchangeability, my method is suchthat this degree of precision is not necessary and it is thus adapted tofield operations where talent and precise machining equipment may not beavailable. Therefore, I will describe the remaining operations as thoughthere were no attempt at interchangeabilitywithout inferring therebythat the mor precise relative dimensioning falls without the scope ofthe: invention.

It may be assumed, for the purpose of illustration, that a given pair ofbox and pipe members is chosen at random from stock without regard totheir precise dimensions, but with the knowledge that the manufacturewas such as to insure that the specified concentricity exists and thatthe space 29a, which is to be developed after the members are threadablyconnected, will be of ample, radially-measured width to take, withrequisite annular clearance, one of the stocked gage rings 35a. Theserings are made of any suitable metal though, for most purposes, I preferto use steel having a yield strength of 40,000 lbs. or more. These ringsmay be provided and stocked in various thicknesses and diameters and maybe continuous, split, or segmental.

The operator measures the diameter of the counterbore 21a of the chosenbox and the outside diameter of the chosen pin it at face 30. From thesemeasurements he determines the width of the space 29a which will bdeveloped when the members are mated, and he selects a ring 35a whichhas such thickness, measured radially, as will be received in thatparticular space and leave annular clearance spaces of uniform capillaryextent between the ring and the opposing peripheral faces of the box andpin members. For instance, if the pin face 38 measures 4.5" in diameterand the counterbore measures 4.75" in diameter, he may select agage ringwhich is 4.506" inside diameter and 4.744" outside diameter. Such a ringwill, when centered Within space 2911, provide an annular,solder-receiving space (.003" wide, as measured radially) between theouter peripheral face 36 of the ring and the'face 31d of thecounterbore, and a solder-receiving space of like capillary dimensionsbetween the inner peripheral face 3? of the ring and the peripheral face3 of the pin.

As noted above, ring 35a may be continuous or it may be split, asindicated in Fig. '7, in which latter case the free end or ends of aring of given thickness and given initial diameter, may be filed orotherwise dressed at the split to reduce the eifective diameter of thering and thus make it possible to adapt the single ring to differentjoint-pairs, where the differentials between the pin and box diameters,at the zone of spaces 290;, are the same in the different joint-pairs,but, as between pairs, the individual diameters vary. The rings, splitor unsplit, are so formed that they are truly round when they arefinally inserted in spaces 29a. Rings of the split type may convenientlybe rolled to shape from material such as gage, shim or fiat-groundstock, for such material comes in a relatively large number ofaccurately gaged thickness dimensions.

Fig. 4 shows ring 35a encircling pipe end It, but before it has beenthrust into space 29a, the ring having been slipped over end it beforeconnection 2| was made up. Fig. 5 shows ring 35a as moved forwardly intoplace within the recess 29a, the capillary spaces between the ring andbox member and between the ring and pin member being indicated at 38 andas, respectively. The ring may be inserted to an extent determined bythe contact of its inner end with the wall S ice of conical counterbore32a, and, preferably, though not necessarily, the outer end of the ringis spaced inwardly from the free end of skirt 28 to form an annularpocket M3.

In its broader aspects, my invention contemplates any suitable procedurefor introducing hard solder to spaces 33 and 3S and, with this solder,creating a rigid bond between the ring r 9 r and the joint members. Ihave illustrated and will now describe, in connection with the presentlyselected embodiment of the invention, certain preferred procedures, butthese references to particularities are not to be considered aslimitative on my broader claims.

It is also to be understood that any procedure or step described inconnection with one embodiment may be substituted for the correspondingprocedure or step described in connection with any other embodiment, solong as they are not precluded by the individual characteristics of suchother embodiments. For instance, while in the embodiment of Figs. 5, 21,26 and 32, the solder is described as introduced from the outer end ofthe gage ring, it is within the scope of the invention to introduce thesolder from the inner ends of the rings in said figuresfor instance, asillustrated in Fig. 13. In general, characteristics of procedure orresults which are inherently possible or consummated in carrying out anygiven embodiment, though described in connection with anotherembodiment, are to be considered to be applied to said given embodiment.

In Fig. 5', one or more rings 4! and 4| of hard solder wire are placedin pocket 49 after gage ring 350, and walls 31a, 32 have been properlyfiuxed, the wire being of a gage to provide, in molten state, an ampleamount of solder to fill spaces 38 and 39., plus a proper allowance forwastage. While the axial positioning of the joint assembly is notcritical during the soldering operation, since capillary action willdraw the solder into spaces 38 and 39 even though the joint axis behorizontal, it is preferable that the joint axis be vertical and thatthe solder ring 40 be uppermost. This generalization, as toaxis-position during the soldering operation, is to be considered asapplied to the variational embodiments later to be described.

In threadably coupling the joint members, the box member may be heatedto expand it sufficiently to enable it to be easily threaded home, thethreaded joint tightening up by subsequent shrinkage when the box cools.

With the joint arranged with its axis vertical and with the inner end ofring 3501. engaged with the tapered defining wall 34a of conicalcounterbore 32a, the ring will be self-centered within the cylindricalcounterbore Zla, it following that the radially measured, capillarywidth of spaces 38 and 39 will be uniform throughout their annularextents.

With the elements arranged in the relative positions of Fig. 5, skirt28a, ring 35a and the zone of pin l8 defined by face 38, are raised tosolderllow temperature. This may be accomplished by any suitable heatingmeans such as a torch, though preferably the heating procedure outlinedin my said co-pending application is followed. This procedure involvesthe use of induction coil heating from either the inside or outside ofthe joint, which procedure has the advantage of giving rapid, easilycontrolled and localized heating effects. Where it is important thatexposed portions of the box and pin members, particularly in thetransverse plane of the ring 35a, be kept from reaching solder-flowtemperature because it is desirable not to disturb the metallurgicalcharacteristics given those portions by pre-heat treatment, thelocalized cooling described in said application may be used toadvantage.

As soon as solder-flow temperature is reached,

capillary action causes molten solder from pocket All to enter andextend itself through spaces 38 and 39, as illustrated at 42 and 43,respectively, 7

in Figs. 6 and 7.

Due to the described relative dimensioning of the joint members and thering and the described centering of the ring within space 290., thesolder bodies 42 and 43 will be of uniform capillary thicknessthroughout their annular extends. In the event the conical shoulder suchas the defining wall of counterbore 32a be not used for selfcenteringthe ring, or if no other mechanical centering means be used, the moltensolder has a tendency to float the ring into centered relation with thepin and box, and therefore the ultimate solder bonds will besufliciently close to uniform thickness to possess strengthcharacteristics suitable for many types of work. However it ispreferable, particularly where the joint is to present maximum strengthcharacteristics, that uniformity of bond thickness be assured by apositive centering of the ring within space 29a.

Upon subsequent cooling of the elements, solder bodies 42 and 43 formbonds of uniform capillary thickness between the pin member, ring, andbox member, and, of course, the solder integrates the free ends 45 ofthe ring if a split ring has been chosen for the particularinstallation. Solder bonds 42 and 53 not only provide a leak-proofconnection between the pin and box members,

but they so immobilize these members with relation to one another as toeliminate loosenesses which otherwise would allow working of the jointparts, and to prevent thread creep under the most severe torque loads.The bond thus eliminates one of the chief sources of pin collapse andbox rupture, as well as other usual causes of joint-failure-all aspointed out in the earlier part of the specification. It will be notedthat ring 35a, having served its purpose as a gage to determine the bondthickness during the soldering operation, now acts as a rigid bridgebetween and integrated with the pin and box members, being as fullyeffective to transmit drive from member to member and to preventrelative longitudinal and relative angular movement between the membersas though those members were one.

Further, the bonded ring 35a acts as a filler for the original annulargap between the pin and box members at a point outwardly beyond the lastengaged thread 33, and thus prevents the members from rocking relativelyabout the zone of this last-engaged thread when the drill pipe isexposed to bending stresses. In so acting, the ring eliminates anotherofthe chief causes of drill stem failure, for the rock point is shiftedto a location (the outer end of ring 35a) on pipeend It where there isno notch effect. Furthermore, solder fillet M merges into peripheralface as, eliminating all abrupt and sharp shoulders at the junction ofthe ring and pin member and therefore greatly reducing the tendency ofthe ring to impose weakening stresses at this new point of rock.

In spite of the fact that the described solderbonded connection, is of anature to resist effectively all forces tending to separate the jointparts during drilling operations, the joint may be broken wilfully whenan occasion arises for removing a given tool joint member from a givenpipe, without the danger of injuring any of the joint parts, includingthe threads. This may be accomplished by reheating the joint parts atthe zone of bond to solder-flow temperature and then vention illustratedin Figs. 3 through 14. In this case the gage ring carries a formationwhich, in its co-action with the opposing walls of the joint members,positively insures uniformity of the capillary spaces throughout theirannular extents, it following that the ultimate solder bonds arelikewise of uniform capillary thickness and therefore have maximumstrength characteristics. The peripheral face 3% of pin end is isconcentric with pin threads 23, while box end 2329 is similar to end23a, except that preferably skirt 25b and space 292) are slightly longerthan skirt 28a and space 29a, respectively. The peripheral face 3 lb,defining counterbore 21b, is true and is concentric with box three. 25.

Ring b, which may he slipped over pin I5 before the joint is threadablycoupled, has at one end an internal annular flange 46 and an externalannular flange a l, the flanges forming, with the radially alignedportion of the ring, proper, an enlarged, annular head 48. Flanges and4? form annular shoulders 49 and 49' which are each of capillary extent,as measured radially of the ring. The body portion 58 of the ring is ofuniform thickness throughout its annular and axial extents, and itsperipheral faces are concentric with the peripheral faces of flanges 46and All. Gage rings having various diameters and various headthicknesses are manufactured and stocked, but in every case shoulders 49are of capillary radial extent. It follows that while the headthicknesses and the thicknesses of body portions 50 may vary as betweendifferent rings, the differential between the head thickness and bodyportion thickness will exist substantially as a constant.

Having chosen at random a pipe member and a box member, the operatormeasures the inside diameter of counterbore 27b and the outside diameterof the pipe at pin face 30, and from these dimensions he selects a ring3% whose head &8 has such inside and outside dimensions as will cause itto fit snugly into space 2% when the pin and box members aresubsequently threadably coupled, and the selected ring is slipped ontothe pin member, as in Fig. 8, prior to the coupling of the joint, theinner peripheral face of the head or flange 46 having close fit with pinface 39.

Ring 35?) may be fashioned in any suitable manner, and it may becontinuous, as in Fig. 9; split as at 35bb in Fig. 10; or segmental asat 351222?) in Fig. 11. In this connection, the same generalization asto ring formation is to be considered as applying to the rings later tobe described and to the appended claims, except where the structuralenvironment of particular embodiments or the phraseology of particularclaims precludes such application.

Where ring 35b is of continuous nature, as in Fig. 9, it may be machinedto size and shape from plain tubular stock, or it may be formed byprocessing plain tubular stock in a cold upsetting die. Where the ringis split, as in Fig. 10, or is se mental, as in Fig. 11, it may becurved to shape after having been cut from flat stock which has beenpreliminarily formed to give it the described cross-sectionalcharacteristics.

After having inserted the ring 4! of hard solder in the counterbore 21band after the joint parts have been screwed together, the gage ring isthrust into space 2% (Fig. 13) head 48 preferably having snug fit withinthat space. Due to the ring, it is assured that annular spaces 38b and391) are of uniform capillary widths throughout their longitudinal andannular extent. If the ring be initially somewhat out of round, thefitting of head 48 over the pin end will true up the entire ring. Itwill be noted that the assurance of uniform, capillary widths is had inspite of the fact that peripheral faces 3!! and 3172 were notnecessarily originally machined to have precise relative diameters.Thus, the operator in the field is able to secure precisely accuratefinal results without having to perform any precise machining operationsand without it being required that the pipe member and box member he hasselected possess any particular relative dimensioning of the boxcounterbore and the portion of the pin to be taken within that bore. Thebasis of the ultimate precise sizing, which is essential to secure thehighest ultimate strength of the soldered connection, is the accuraterelative dimensioning and arrangement of the body and flange portions ofthe gage ring. Since these rings come to the field in accurate form fromplants where the requisite accuracy is easily accomplished, theyrepresent no machining problem to the field install-er.

With the elements in the condition of Fig. 13, the soldering operationis carried out as described in connection with Figs. 6 and 8, giving thefinal effect of Fig. 14, where the solder has entered the spaces 33b and397) by capillary action and, when cooled, has formed the solder bonds4% and 13?: which are of uniform capillary thickness throughout theirannular and'axial extents, giving all the beneficial results spoken ofin connection with Fig. 8, plus the added benefits arising from thepositive exactness of the uniformity of bond thickness,which'un'iformity has been positively assured by reason of the describedring formation as distinguished from the plain ring of Fig. 6.

During the soldering operation, the joint is preferably positionedvertically, withsolder ring 4| uppermost. However, should the jointextend horizontally during the soldering operation, the solder may beprevented from flowing into the counterbore 3212 instead of into spaces33b and 39b, by proper heat control. That is, localized heatingand'cooling may be established, as described in my aforesaidapplication, so ring 3% solder 4| andthe adjacent, co-planar portions ofmembers 23b and I6 are heated to solder-flow temperatures, while theportions of members 2321 and I 6 which lie to the right of solder ring3! (as viewed in Fig. 13) are held below this temperature.

In the embodiment of Figs. 15 through 17, the same general principlesare employed as in Figs. 8 through 14, except that the ring andcounterbore formations are such that the inside and outside diameters ofthe gage ring head need not be of closely accurate dimensions in orderto be taken properly within a given annular space existing between thepin and box member of a given joint-pair. The number of different sizedstock rings necessary to insure that there will be one to fit any givenpair of stock pin and box members, is thus materially reduced.

The formation of counterbore 21c differs from that of counterbore 21b inthat the latter is cylindrical while 210 is conical. Ring h ad i dc andbody portion Silo are externally conical, the taper of counterbore Wall3E0 being of the same degree as the taper of the peripheral face 3E0 ofbody portion 500 and the taper of peripheral face 5% of flange 470.However, external shoulder 49, as well as internal shoulder 49, is ofcapillary ex- 13 tent, measured radially, and, considered in atransverse cross sectional plane, face 360 of body portion G0 isparallel to the peripheral face 5| of external flange ile. When givenbox and pin members have been chosen, the operator selects a ring 350whose head 480 will fit space 29c at any point which will insure theproper longitudinal positioning of the body portion 59c within thespace. The inside diameter of the head must be at least as great as theoutside diameter of pin IS at face 38 and the outside diameter of thehead must be sufiiciently small to enter the relatively wide mouth ofopening 290, but between these limits the ring diameters may varyappreciably and still be adaptable for the purpose.

Suppose, for instance, that the internal flange 46 of a selected ringfits the pin nicely. The ring is merely thrust into opening 290 untilthe external flange 47c engages counterbore wall 350, and, by pressingthe ring head firmly to seat, the tapered faces 5! and Sic willthereafter co-act to hold the ring in a position to insure the spaces38c and 390 (Fig. 16) are of capillary widths. On the other hand, ifflange 46 has loose fit about pin' 16, the ring is forcibly thrust homeafter tapered faces 5! and Bio engage, the resulting wedge or swagingeffect radially contracting the ring to diminish the inside diameter ofhead 48 until internal flange 46 peripherally engages pin face 30 (Fig.16) thus insuring that spaces 38c and 390 are individually of uniformcapillary width in spite of the fact that originally the internal flangewas annularly spaced from the pin. Or, if the oversize ring beoriginally split, with the split ends spaced apart when first applied tothe pin, the wedge action between the tapered faces of the head andcounterbore wall will re.- dially collapse the ring about the pin, andthe split ends of the ring will be drawn toward one another.

The hard solder ring 4! is applied and the soldering operation iscarried out as described in connection with Figs. 13 and 14, the finalresult being that represented in Fig. 1'7 wherein the solder bonds 42cand 430 are shown to be individually of capillary thickness throughouttheir annular and longitudinal extents, with all the attendantadvantages.

The embodiment of Figs. 18 to 20 illustrates a situation wherein the pinend [Ed has a conical external upset 52, the taper of peripheral-face39d being complementary to that of wall 3id of counterbore Zid. Itfollows that when pin Hid and box 23d are threadably mated, as in Fig.20, annular space 29d is of uniform width throughout its longitudinalextent, though its bounding walls are conical. The peripheral face Eidof head 486! or flange Md is complementary to face 31d, and theperipheral face 53 of head 38d or flange 66d is complementary to pinface 38d. Faces Std and 31d of body portion 50d are parallel and havethe same taper as faces Sid and 53d. As in the previous cases, shoulders4d and 49 are of capillary extent, measured radially.

The operator choses a. ring 35d whose head GM will snugly fit space 29dwhen the joint is subsequently made up, and he slips this ring onto piniiid prior to threadably mating the pin and box members. Preferably, theconical ring is moved to the position it will finally occupy on the pin(Fig. 18) as determined by the full engagement of conical face 53d withconical face 3%. After applying hard solder ring 4| to the pin, box 23dis screwed home on pin "id, and skirt 28d will move over ring 35:2 tothe position of Fig. 19, at;

which time conical head face 55d will be engaged by conical face 31d. Insome instances, the? method is most advantageously carried out byselecting parts having such relative dimensions, that as the box membershrinks about the pin member, the shrink causes face Sid to tightlyengage ring face 51d. As before, capillary spaces 38d and 39d, ofindividually uniform widths throughout their annular and longitudinalextents, will be defined by opposed peripheral faces of the ring andjoint members. The soldering operation is then carried out as previouslydescribed, and the final result is that illustrated in Fig. 20, whereinsolder bonds 52d and 43d are of capillary thickness and integrate thejoint parts with all the beneficial effects mentioned in connection withthe previously described joints.

In the embodiment illlustrated in Figs. 21 to 23, the pin member l6 andcounterbore 210 have the same characteristics as the corresponding partsin Fig. 15, the peripheral face of the pin being cylindrical and theperipheral face 3lc of the counterbore being conical. In this case,however, head 48 is provided at the smaller end of the external taper ofgage ring 35f (Fig. 22). Cylindrical faces 31 and 53 are concentric, thelatter defining a bore adapted to take pin l6. Conical faces 36 Elf andtie have the same degree of taper, the ring head 48 having such outsidediameter that it will engage counterbore wall 3lc when moved to properposition within the annular space 290 after the joint parts have beenmated as in Fig. 21. everything said as to the fitting of ring 350within conical counterbore 210 of Figs. 15 to 17, applies also to thefitting of ring 35 within the associated counterbore.

Fig. 21 illustrates gage ring 311 in position for soldering, thecapillary spaces 38f and 39f possessing the characteristics ascribed tothe previous embodiments except that, as distinguished from Figs. 13, 16and 19, they open to pocket 40 wherein the solder ring 4| is placed. Thesoldering procedure may be the same as that described in connection withFigs. 5 and 6, resulting in bonds 32 and 43 of capillary andindividually uniform thickness (Fig. 23) and giving tothe completedjoint all of the advantageous characteristics mentioned above.

The provision of head 18 at the inner end of the gage ring has theadvantage of providing a stop or dam for preventing solder flow intocounterbore 32c, thus eliminating solder wastage and insuring that thespaces 38 and 38] are filled with solder even though the defining wallsof counterbore 320 be heated to solder fiow temperature. It also allowsthe formation of a solder fillet 44 at the outer end of the ring,thereby eliminating an abrupt shoulder between the gage ring and pin atthis rock point. It will be understood that it lies within the scope ofmy invention to provide this feature of a head at the inner end of thering in substitution for the heads at the outer ends of the ringsillustrated in connection with the other embodiments.

The embodiment shown in Figs. 24 through 27 is especially well adaptedto a situation where the zone of the pipe or pin member which is to betaken within the box skirt, requires machining to put it into propersolder-receptive condition or to render it truly concentric with the pinthreads. However, it broadly contemplates any situation Where the zoneof the pin which is to be encircled by the box skirt is of lesserdiameter than are the thread crests of the pin.

Thebox and counterbore formations may exactly the same as in Fig. 4, andtherefore need,

It will be noted that,

reduced external be no further described. However, pin endl6g is turnedor ground down to product a zone of diameter, circumferentially boundedby peripheral face 339 which is truly concentric with pin threads 24.The turning operation will ordinarily remove most or all of the originaldie-out threads of the pin and may even include one or more of theadjacent full pin threads.

Aring 35g is thenchosen which has the proper thickness characteristicsto enter space 299 and leave the described solder-(receptive clearancespaces. Since the outside diameter of zone 54' is less than the crestdiameter of threads 24, itis impossible to use a continuous gage ringhaving an initial internal diameter which is greater than the diameterof face 399 by only capillary extent, unless special steps are taken.While a split ring or segmental ring having proper dimensionalcharacteristics may be applied to the reduceddiameter zone, as will bereadily understood and as is contemplated as included in this embodimentof the invention, Figs 24 to 27 also illustrate a method of employing acontinuous, radially deformable ring 355/ in the described situation.

If ring 359 be of the continuous type, it is chosen not only to have thethickness characteristics specified above but also to have an insidediameter which will enable it to be slipped over the pin threads to theposition of Fig. 24. Then, before or after box member 230. is threadablyconnected to the pin, a radial swaging device, conventionallyillustrated at 55 in Figs. 24 and 25, is applied to the ring and isoperated to deform or contract the ring radially to an extent that itmay be subsequently thrust into space 29: and leave the.requiredcapillary spaces 38g and 399 (Fig. 26).

If the ring he made of a metal having no appreciable resilientcharacteristics, the swaging device will be operated to exert itscontractive force only to such an extent that the inner face of the ringis properly annularly spaced from face 30g, and

suchan operation is Within the scope ofmy in- I take advantage of thisally outward to an extent which will leave 'an- 1 annular space ofpredetermined, uniform capil-' lary width between it and peripheral face3119!.

This eliminates the necessity of checking the swaging operation at theprecise instant a capillary spacing exists between the ring and pin, asis true where the swaging operation is depended upon to contract thering to its final size.

For instance, assume the diameter of pin [6g is 4.4375 at zone and thatspace 29g is .125 wide. A ring 359 is made up of steel having a yieldstrength of 40,000 lbs., the ring having an inside diameter of 4.5625"and an outside diameter of -e.8(i05". This ring is slipped over the pinto the position of Fig. 24 and swage 55 is operated to contract ordeform the ring radially until it engages peripheral face 3%. When theswage is subsequently backed away fromthe work, the ring, because of itsascribed characteristics, expands radiall a precalculable extent,namely, to

an inside-diameter "of 4.41435". Then, when the ring is'thrust-intospace 29g, there will be found to exist the desired, radially measured,annular spaces-of .003" between the ring'and pin and-between the ringand'counterbore 3lg (Fig. 26).

Thus, with available knowledge of the springback characteristics ofvariousmetals, the operator may select theparticular ring-metal which'will give to the ring the final dimensional characteristics necessary tothe given relative dimensional characteristics of the chosen pin and boxmembers, and then merely swage the ring down to the pin, with theassurance that when the swageis removed from the work,theproper'relative'dimensions of ring and joint memberswill exist.

It-will be understood that the described swaging operation may beadvantageously applied in connection with any-of the previously orherein- -after described embodiments wherein a con-' tinuous type ofring is employed, providing the ring-be of the proper thickness andinitially have" an inside diameter which clears the peripheral face ofthepin by more than capillary extent.

With the joint elements and solder ring ii in the condition of Fig. 26,the soldering operation may proceed as described in connection with theprevious figures, the final effect being that illustrated inFig. 27wherein the ring and the solder bonds '42 and 53 have the samecharacteristi'cs and beneficial results as those described in connectionwith Fig. 6.

In the embodiment illustrated in Figs. 28' through .30, I have shown asituation wherein only the external flange is employed on the gage ring,

the inner capillary space being gaged by estab' lishinga predetermined,reduced diameter zone on the pinmember of the joint.

In this case, counterbore 2H1, may have the general characteristics ofcounterbore 270 (Fig. 15) except that as a feature which may beincorporated in this or any other of the embodiments (thoughnot-necessary to thisor any'other such embodiment) an annular groove orsolderreservoir 56 may be cut at the junction of counterbore 12th and32h to receive and hold the solderring 61h.

Ring 35h has only one flange, namely, the external flange 47h, the taperof whose external face 5 Eh has the same degree of taper as counterboreWall 3l-h and as-the peripheral face tth'of body portion 53h. On theother hand, the bore of ring SEh-is of uniform diameter throughout itsaxial extent. Zone 54h is of reduced diameter, as in the case of zone 52- in Fig. and is concentric-With pin threads 26.

Peripheral face 5? ofzone 54h extends to a point which is spaced.inwardly fromthe mouth of counterbore 'i'ih when the joint is made up.At the inner end 'of zone 5th, the pin is turned down to provide a zone58 of still further reduced diameter, this zone being peripherallydefined by cylindrical face 39h. Shoulder 59 at the junction of zones54h and 58, is of capillary radial extent.

In making up the joints represented by this embodiment of the invention,a ring 35h is chosen which has the proper thickness characteristics tofit the given pin and box pair, as has been generally described inconnection with the other embodiments and as more particularly describedin connection with Figs. 15 to 17 wherein the counterbore and externalring'flange are tapered; With solder ring 4|" within groove 56 and withring 35h encircling zone 54h, the joint is threadably mad'e u asiin'Fig.-28'3-f-R.ing 3571.

is then thrust toward the position of Fig. 29 until head 487i is tightlyfitted within space 29h,"the" wedge coaction of faces'tlh' and 5171.during the movement 'of the ring serving to contract the ring radiallyuntil the outer end'iartion of face 31h engages pin face 53h, and theremainder of ring face 31h is radially spaced from pin face 39h bycapillary extent, as amen. If the selected r'ing- 35h forig'in'ally has"sufiiciently close fit on zone 54h, the 'wedge 'coaction "of faces3H1." and Elh may be utilized solely for establishing the final positionof the ring within space 29h.

When the joint is exposed to soldering temperatures, as described inconnection with the earlier embodiments, the solder of ring llh willflow into capillary spaces 38h and 3% to form solder bonds 42h and 43h(Fig. 30) of uniform, capillary thickness, all to the advantageous endsspoken of above.

The embodiment illustrated in Figs. 31 to 33 is particularly welladapted to treatment of -it is possible that the machining may vary asbetween individual pin members. Of course, the above general treatmentdoes not at all preclude the provision or fabrication of a special gagering to suit the requirements of any particular given box and pin pair,and such special provision or fabrication lies within the scope of myclaims.

The pin I6 of Fig. 3 is preferably turned down as in Fig. 31 to providea zone 86 of reduced diameter, the cylindrical face 36k of this zonebeing concentric with relation to pin threads 2d,

and said face or zone may have a diameter substantially equal to theroot diameter of the full pin threads. With given ultimate strengthrequirements, the cut producing zone 60 will be sufficiently deep toinsure that, when the joint parts are mated, there will be an amplelongitudinal extent of unthreaded pin surface encircled by skirt 28, toprovide a proper solder receiving space between the gage ring and pin.It is to be borne in mind, however, that there are occasions where thestrength demands are sufficiently low that the normal, unthreaded extentof the pin encircled by the skirt, as in Fig. 3, is sufficient to servethe purpose, in which case a relatively short and thin gage ring may beused and the procedure described in connection with Figs. 4 to 6 may befollowed.

After reduced-diameter zone 60 is formed, a ring 35k is chosen whichwill fit, with described capillary clearance, a particularpin l6 and astandard box 23. The ring may be of any of the types previouslydescribed so long as it is capable of being initially applied to a pinzone which is of less diameter than the crests of .the pin threads. Ifthe ring be of the continuous type, it may be swaged to size, asdescribed in connection with Figs. 24 and 25. If it be of the split typeshown in Fig. 31, it will be sprung radially sufficiently to allow it toclear the pin threads as it is moved to the position of that figure.When it springs back or is otherwise 1-8,. radially contracted to an:extent causing split. ends 45 to meet, it will be assured-that it. hasthe; characteristics proper. to give the desired capillaryclearanceeffects during the latersteps-of the,

process. 7 V

In Fig. 32 ,the ring'is illustrated as being in its condition of finalradial contraction and as having been thrust into annular spa'ce29k, thering b'e'ingicentered within counterbore 21 by. the 'co'ntact of theinner end of the ring witli face 31h of conical counterbore 32, it thusbeing assured that spaces 38 and 39k are of uniform capillary widththroughout their annular and axial extents. Or, as explained earlier, ifno positive centering means be employed, the floating effect of themolten solder will float the ring to a position so close to center as togive final solder bonds sufiiciently close to conditions of uniformityas will satisfy strength requirements of relatively low order.

Solder ring 4| is then positioned as illustrated in Fig. 32 and thesoldering operation is carried out as described in connection with Figs.5 and 6. The final effect is that illustrated in Fig. 33, wherein solderbonds 42k and 4370 are of uniform thickness, and those bonds, as well asring 3570 and solder fillet 24k, serve the advantageous ends spoken ofin connection with corresponding elements in Fig. 6.

While I have shown and described preferred embodiments of my invention,it is to be understood that various changes in design, structure andarrangements, as well as changes in the order of certain of the methodsteps, may be made without departing from the spirit and scope of theclaims appended hereto.

I claim:

1. A drill pipe connection embodying a box member and a pin memberthreadably connected in axial alinement, an inserted ring betweenopposed peripheral faces of the members, a radially projecting, annularflange on the ring and engaging the peripheral face of one of themembers, and a hard solder bond of capillary thickness between themembers and the unflanged portion of the ring.

2. A drill pipe connection embodying a box member and a pin memberthreadably connected in axial alinement, an inserted ring betweenopposed peripheral faces of the members, radially projecting, internaland external annular flanges on the ring and engaging the opposingperipheral faces of the members, and hard solder bonds of capillarythickness between the members and the unfianged portions of the ring.

3. A spacer for insertion in the counterbore of the box member of asoldered pipe connection, embodying a ring, and an integral annularflange extending, in capillary amount, radially from one of theperipheral faces of the ring.

4. A spacer for insertion in the counterbore of the box member of asoldered pipe connection, embodying a ring, and a pair of integral, an-

nular flanges extending, one each and in capil- 19' extending, incapillary amount, radially from one of the peripheral faces of the ring,the peripheral face of the flange and said one peripheral face of thering being conical and of substantially the same degree of taper.

' ALBERT L. STONE.

REFERENCES CITED Number 20 STATES PATENTS Name Date Rader Oct. 11, 1932'Spang Apr. 30, 1935 Herr June 18, 1935 Young Sept. 8, 1936 Burkart June8, 1937 Reimschissel Nov. 28, 1939 Boynton Mar. 18, 1941 Gray July '15,1941

